Conveyor device running on rails

ABSTRACT

A rail-travelling conveyor device to be advanced supported by two mutually parallel rails, comprising: a carrier frame, a load compartment substantially firmly connected with the carrier frame, said load compartment being arranged at least partly below the rails, said load compartment having a maximum extent in the longitudinal direction of the rails, a plurality of driving wheels engaging the rails, at least one motor which is connected with the conveyor device and which drives at least one driving wheel. The device is characterized by each driving wheel having a separate rotational shaft connected with the carrier frame, said rotational shafts having rotational axes fixed with respect to the carrier frame, said rotational shafts being arranged within the said maximum extent of the load compartment in the longitudinal direction of the rails, and guide means to guide the conveyor device through curves.

The present invention concerns a rail-travelling conveyor device to beadvanced supported on two mutually parallel rails and comprising acarrier frame, a load compartment substantially firmly connected withthe carrier frame, said load compartment being arranged at least partlybelow the rails, said load compartment having a maximum extent in thelongitudinal direction of the rails, a plurality of driving wheelsengaging the rails, and at least one motor which is connected with theconveyor device and which drives at least one driving wheel. In thisconnection, "firmly" means that, when being advanced, the loadcompartment is connected with the carrier frame in such a manner thatthe location of its centre of gravity substantially cannot change withrespect to the carrier frame, i.e. the load compartment cannot pivotfreely like a pendulum.

Conveyor devices which travel on rails and are used e.g. to feed viscousmasses through production systems, are generally known. The conveyordevices may be advanced supported by rail systems, which comprise asingle rail or two rails extending mutually in parallel, and which areeither supported by columns or are suspended from an overhead structure.The rail systems used may be provided with upward gradients in thelongitudinal direction, as required, and may comprise curved tracksegments and switches allowing the travelling direction of the conveyordevices to be changed.

Whether one rail system or another is selected for a given productionsystem usually depends on the occurring loads from the conveyor devicesand on the mutual location of the production buildings. Further, theselection may determined by the simplicity with which the loadcompartments of the conveyor devices must be capable of being filledwith the viscous mass. Particularly in connection with rail systemshaving two rails extending mutually in parallel, it is possible to fillthe conveyor devices from a position centrally above the loadcompartment, without the access to the access opening of the loadcompartment being blocked by a rail.

An example of a known conveyor device of the type described in theopening paragraph has been manufactured by the applicant. This knownconveyor device is used particularly in production systems for theproduction of cast concrete objects. In such production systems, thecasting of the concrete objects is usually performed in a separateproduction building which is located at a distance from the productionarea where the wet concrete is produced. It is thus necessary to be ableto transport the liquid concrete rapidly and reliably from one locationto another, and this is expediently done by means of the described,known conveyor device, whose load compartment is filled at a fillingstation in the production building.

However, with this known conveyor device which is advanced supported bytwo mutually parallel rails, special measures have to be taken when theconveyor devices are to travel through curves. For the conveyor deviceto travel through curves and bends, the rotational shafts are mounted soas to be rotatable also with respect to the load compartment about avertical axis, thereby avoiding derailing of the conveyor devices inthe-bends. Thus, the conveyor devices have conventionally been providedwith two separate (two-wheeled) bogies arranged in front of and behindthe load compartment and connected with the carrier frame of theconveyor device by means of a complicated pivot joint. A separate drivemeans in the form of a motor on the bogie has moreover been mounted inorder to propel the conveyor device. In situations where it is necessaryto connect all the driving wheels with a drive means, it is thusnecessary to mount a drive means on each bogie.

The complicated pivot joint between the bogies and the need for twoseparate drive means, however, have made the production of the describedconveyor devices difficult and more expensive, and, accordingly, anobject of the present invention is to provide a simplified conveyordevice, which must also be capable of being advanced through bendswithout any risk of derailing. Further, the conveyor device must also becapable of being produced at a lower cost than the known conveyordevices and moreover be cheaper to operate and maintain.

This is achieved according to the invention by means of a conveyordevice of the type described in the opening paragraph, said conveyordevice being characterized by each driving wheel having a separaterotational shaft connected with the carrier frame, said rotationalshafts having rotational axes fixed with respect to the carrier frame,said rotational shafts being arranged within the said maximum extent ofthe load compartment in the longitudinal direction of the rails, and byguide means for guiding the conveyor device through bends.

When the driving wheels are provided with separate rotational shaftslocated within the said maximum extent of the load compartment in thelongitudinal direction, and when guide means are provided for guidingthe conveyor device through curves, while the rotational shafts haverotational axes fixed with respect to the carrier frame, it hassurprisingly been found that it is possible to drive the conveyordevices through bends without any risk of derailing, with anuncomplicated and low-cost bearing structure, while still providingunobstructed access to the load compartment during filling. As the loadcompartment is arranged at least partly below the rails, so that thecentre of gravity is located below the driving wheels, the conveyordevice does not tend to tilt during acceleration and deceleration. Thus,it is an essential feature of the invention to avoid a structure withdrive shafts that extend between the rails and may thus interfere withthe filling of the load compartment or with the storage of the viscousmass in the load compartment, while still allowing the conveyor deviceto be driven through bends.

The invention moreover allows the driving wheels to be arranged close toeach other in the longitudinal direction, so that the conveyor devicescan follow the rails in bends and curves with an even smaller risk ofderailing.

The invention provides special advantages when the load compartment hasan access opening, particularly a filling opening, arranged at aposition between and preferably also above the rails, and optionally adischarge opening disposed at a distance below the rails, as the fillingopening may preferably have the same dimensions as the load compartment.

When, as stated in claim 3, the conveyor device is provided withrespective drives extending at least partly along respectivelongitudinal sides of the load compartment, said respective drivesconnecting at least one respective driving wheel with a drive means, itis possible to connect the driving wheels with a single propellingdevice which may be arranged in front of or behind the load compartment,and which has a drive take-off that may extend to the longitudinal sidesof the load compartment.

In a particularly expedient embodiment, the guide means may moreover bearranged on the front and rear ends, respectively, of the carrier framewith respect to the direction of travel and may engage the rails toguide the conveyor device through the curves.

In a further embodiment, the conveyor device may comprise four drivingwheels and support means arranged on the front and rear ends,respectively, of the carrier frame with respect to the travellingdirection to prevent tilting of the conveyor device under special loads,as, in that case, the support means will provide a support against therails. This embodiment is particularly expedient in situations where thedriving wheels are arranged two and two above each rail with arelatively small mutual spacing. It is also possible to use the supportmeans when just two driving wheels are used.

According to special embodiments of the invention, the guide meansand/or the support means may comprise a carrier element having twoseparate guide wheels and support wheels, respectively, said carrierelement itself being mounted for rotation about an axis which extendsperpendicularly to the rotational axes of the driving wheels. Thisenables the guide wheels and the support wheels to yield when movingthrough bends. The respective carrier elements may be arranged forrotation about a common shaft in a particularly advantageous manner,thereby providing a particularly simplified structure.

It is moreover within the scope of the invention to advance the conveyordevices in engagement with rail systems, where the inner or the outerrails in the curves are provided with a coating of a material of lowfriction on the travelling surfaces. Hereby, e.g. errors in thetravelling geometry may be avoided.

The invention will be described more fully below with reference to anon-limiting embodiment shown in the drawing.

FIG. 1 schematically shows a known conveyor device, seen in perspectiveview,

FIG. 2 schematically shows a conveyor device according to the invention,seen in perspective view,

FIG. 3 is a front view of a carrier frame for a conveyor deviceaccording to the invention, supported by two parallel rails,

FIG. 4 is a top view of the carrier frame illustrated in FIG. 3,

FIG. 5 is a lateral view of the carrier frame illustrated in FIG. 3,

FIG. 6 is a lateral enlarged view of a carrier element according to theinvention,

FIG. 7 schematically shows the conveyor device according to theinvention when travelling through a bend.

FIG. 1 schematically shows a known conveyor device 10, which is marketedby the applicant. The conveyor device is used particularly in productionsystems for producing cast concrete objects and is advanced supported bytwo mutually parallel rails 1, 2. The conveyor device comprises acarrier frame 8, which is firmly connected with a load compartment 5having a first or upper opening located in a plane above the rails, saidload compartment 5, as indicated in broken line, extending at a distancebelow the plane of the rails and being provided with a second or loweropening (not shown), which may be blocked, and which is used foremptying the load compartment. The conveyor device is moreover providedwith four driving wheels 3 connected in pairs with rotational shafts,which extend transversely between the rails, and which are arranged infront of and behind the load compartment. To enable the conveyor deviceto travel through bends and curves, each of the rotational shafts ismounted for rotation with respect to the load compartment 5 about avertical axis 6 so as to avoid derailing of the conveyor devices in thebends. Basically, this results in a structure with two separate bogieswhich are connected with the carrier frame of the conveyor device bymeans of a pivot joint 6. A separate drive means in the form of a motorwhich drives the wheels, and a brake are mounted on each bogie.

FIG. 2 schematically shows an embodiment of a conveyor device 20according to the invention. The conveyor device travels on two parallelrails 21, 22, which may particularly be formed as I profiles having anupwardly directed engagement flange, which expediently forms a carrierface for the driving wheels and support means described below. The railsmoreover have a web part which may expediently form an engagement facefor the guide means also described below. As will appear, the conveyordevice is particularly expedient for use in connection with rail systemshaving curved rail segments of the type shown in FIG. 2.

The conveyor device 20 is constructed with a carrier frame 25 firmlyconnected with a load compartment 26, which has an upper filling openingand a lower discharge opening 30 provided at a level below the rails.The conveyor device is used particularly expediently in systems whereviscous masses, such as liquid concrete in particular, are to beconveyed rapidly and reliably from one location to another, said loadcompartment being filled from above at a filling station and emptied atan emptying station located at e.g. floor level below the loadcompartment and between the rails. The shown load compartment 26 has anextent L in the longitudinal direction of the rails and may optionallybe provided with partitions (not shown) which divide the loadcompartment into independent cells. The conveyor device is additionallyprovided with four driving wheels 36, of which only two are shown in thefigure, and which, in pairs, engage the upper flange of a respectiverail 21, 22. The driving wheels may advantageously be constructed asrubber wheels, as the deformation of the rubber material facilitates thetravel of the conveyor device through curves. To ensure free access fromabove to the load compartment, each driving wheel has a separaterotational shaft, which is mounted on the carrier frame 25, and whichextends on the outer side of the boundary walls of the load compartment26. The rotational shafts are fixed with respect to the carrier frame,in the sense that the driving wheels cannot be steered to provide achange in the direction of travel of the conveyor device. It is anessential feature of the invention that the driving wheels 36 arearranged along the extent L of the load compartment 26, preferablyrelatively close to the line of symmetry at L/2, so that only a limiteddisplacement of the wheels transversely to the rails will take place inbends, thereby obviating derailing of the conveyor device when ittravels through the curve shown. The carrier frame 25 moreover mounts adrive motor (drive means) 35 connected by means of suitable drives withthe driving wheels to drive these.

Reference is now made to FIGS. 3-5 which show an embodiment of a carrierframe 25 for the conveyor device of the invention in greater detail. Thecarrier frame is composed of two parallel and longitudinal beams 28 anddefine a rectangular area in which a load compartment may be mounted.For clarity, the load compartment is not shown, but it will beappreciated that a load compartment is preferably firmly connected withthe carrier frame 25 between the beams 27, 28 to be arranged at leastpartly below the rails 21, 22, as the load compartment 25 is to befilled from above from a position between the rails. A propelling motor35 is mounted on one of the transverse beams 28 of the carrier frame. Asmentioned above, two mutually spaced driving wheels 36 are mounted alongeach of the longitudinal beams 27, and, according to the invention,these driving wheels have individual, separate rotational shafts 37which are mounted on the beams.

As appears from FIG. 5 in particular, the propelling motor 35 isconnected to the driving wheels by means of respective drives 39, eachdrive extending at least partly along an associated longitudinal beam27. It is hereby possible to drive the conveyor device by means of asingle propelling motor which can drive all the driving wheels, whilethe conveyor device may be advanced through curves by guide means 40,which are preferably arranged on the front and rear ends, respectively,of the carrier frame 25 with respect to the direction of travel at adistance from the driving wheels, and which can engage the vertical webpart of each rail 21, 22. Preferably, drives are provided along bothlongitudinal beams so that all driving wheels may be driven, but in somesituations it may be relevant not to drive all the drawing wheels.

Each guide means 40 may engage a rail either directly or indirectly andcomprises a carrier element 44 in the example shown. The carrier element44, shown in greater detail in FIG. 6, carries a pair of rotatable guidewheels 40', 40" and is rotatable itself with respect to the carrierframe about a vertical axis 42.

To ensure that the conveyor device does not tilt during e.g. fastaccelerations or decelerations in those cases where the driving wheelsare arranged very close to each other on each longitudinal beam 27, thecarrier frame is moreover provided with support means 46, which arelikewise arranged on the front and rear ends, respectively, of thecarrier frame with respect to the direction of travel. Like in theexample shown, the support means 46 may be formed by a carrier element47, which carries a pair of rotatable support wheels 46', 46", and whichis rotatable with respect to the carrier frame about the said, verticalaxis 42. As will be seen from FIG. 6, the carrier element 47 of thesupport means 46 may be connected with the carrier element 44 of theguide means 40 by a connecting part 100, which results in a quite simplestructure. As appears from FIG. 3 in particular, the connecting part 100is angled. The carrier elements 44, 47 and the connecting part 100 areconnected with a pipe section 105, which is received in a bushing 110mounted on the carrier frame. A spring device 120 is received between anend face 115 in the bushing and an engagement face in the pipe sectionto provide for spring cushioning of the conveyor device and to allowunobstructed movement of said device through upward and downwardgradients along the path of travel. The pipe section 105 can rotateabout the vertical axis 42 by means of a pin connection 130.

FIG. 7 schematically shows a conveyor device according to the inventionwhen travelling through a bend. In the figure the rails 21, 22 are justillustrated with their web part. As appears, the guide wheels 40 engagethe outer rail 22, thereby guiding the conveyor device through the bend,as the driving wheels 36 will be displaced slightly transversely to theupper horizontal flange of the rail. To minimize motion of the conveyordevice transversely to the rails in the bend, the web part of theinternal rail 22 has welded thereon a supplementary flange part, whichis so adapted that also the internal guide wheels engage the rail. Thisresults in extremely reliable travel of the conveyor device through thebend. As appears, the carrier elements 44 will adjust themselvestangentially to the rails at any time.

EXAMPLE

The conveyor device shown in FIG. 2 was constructed with a frame havinga length dimension L of 2200 mm and a transverse dimension of 2000 mm.The load compartment 26, which was connected with the frame, had anopening at the upper side of the frame with a length dimension of 1500mm and a transverse dimension of 1500 mm, and extended at a distance of1100 mm below the rails and was provided with a discharge opening atthis location. The conveyor device was advanced on rails by means of twopairs of driving wheels 36, each pair of driving wheels being advancedon the upper flange of a respective rail. The driving wheels had adiameter of 320 mm and were mounted with a mutual centre distance (shaftdistance) of 500 mm on each side of the line of symmetry of the frame.

I claim:
 1. In a rail-travelling conveyor car (20) adapted to beadvanced supported by two mutually parallel rails (21, 22), comprising:acarrier frame (25), a load compartment (26) substantially firmlyconnected with the carrier frame (25), said load compartment (26) havinga predetermined maximum extent (L) in the longitudinal direction of therails (21, 22), a plurality of driving wheels (36) engaging the rails(21, 22), and at least one motor (35) which is connected with theconveyor car (20) and which drives at least one driving wheel (36), theimprovement comprising said load compartment (26) being arranged atleast partly below the rails (21, 22), each driving wheel (36) having aseparate rotational shaft (37) connected with the carrier frame (25),said rotational shafts (37) having rotational axes fixed with respect tothe carrier frame (25), said rotational shafts (37) being arrangedwithin the said predetermined maximum extent (L) of the load compartment(26) in the longitudinal direction of the rails (21, 22), and guidemeans (40) adapted for engagement with the rails for guiding theconveyor car (20) through curved sections of the rails, said guide means(40) being arranged at a distance from the driving wheels (36) in thedirection of travel of the conveyor car (20).
 2. The rail-travellingconveyor car according to claim 1, wherein bysaid load compartment hasan upwardly open access opening provided between the rails, said accessopening being arranged above the rails.
 3. The rail-travelling conveyorcar according to claim 1, havingrespective drives extending at leastpartly along respective longitudinal sides of the load compartment, saidrespective drives connecting at least one respective driving wheel witha drive means.
 4. The rail-travelling conveyor car according to claim 1,wherein in the guide means are arranged on the front and rear ends,respectively, of the carrier frame with respect to the direction oftravel.
 5. The rail-travelling conveyor car according to claim 1,havingfour driving wheels, and support means arranged on the front andrear ends, respectively, of the carrier frame with respect to thedirection of travel to prevent tilting of the conveyor car.
 6. Therail-travelling conveyor car according to claim 1, whereinthe drivingwheels are arranged approximately symmetrically about the centre line ofgravity of the conveyor car, and the driving wheels are optionallyarranged with a mutual centre distance of between about 1 and about 3times the diameter of the driving wheels.
 7. The rail-travellingconveyor car according to claim 1,each guide means comprises a carrierelement with separate guide wheels, and that the carrier element isrotatable with respect to the carrier frame.
 8. The rail-travellingconveyor car according to claim 5, wherein ineach support meanscomprises a carrier element with two separate support wheels, and thecarrier element is rotatable with respect to the carrier frame.
 9. Therail-travelling conveyor car according to claim 1, wherein the guidemeans and the support means are rotatable in pairs with respect to theconveyor car about the same axis.
 10. A rail-travelling conveyor caraccording to claim 1, wherein the motor is mounted on the carrier frame.11. The system having rail-travelling conveyor cars according to claim 1and having two parallel rails, wherein the upper travelling faces of theouter or the inner rails in the curves are provided with a coating of amaterial of low friction.
 12. The system according to claim 11, whereinthe rails have a substantially upwardly directed flange, and the drivingwheels engage said flange.